Method for purifying a thermoplastic norbornene resin, a substrate using such a resin, and a magnetic recording medium using such a substrate

Abstract

A thermoplastic norbornene resin is purified by using a cleaning liquid to eliminate organic impurities, ionic impurities, metallic impurities, and particles of the resin. The cleaning liquid is selected from 2-propanol and a mixed solvent of 2-porpanol and water. A subtrate for a magnetic recording medium of the invention is fabricated by injection-molding the thermoplastic norbornene resin purified by this method. A magnetic recording medium of the invention includes such a subtrate, and a magnetic layer, protective layer, and a liquid lubricant layer sequentially formed on the subtrate. A method for manufacturing such a magnetic recording medium is also provided.

Dependencies are inferred from the claim text.